For purposes of discussion, the prior art connectors will be divided into two groups. The first group includes crimpable connectors for use with electrical wires and the like, and the second group relates to fiber optic connectors.
In the prior art there are many different crimpable terminals. The majority of these prior art crimp type terminals utilize a metal barrel into which the end of a wire is positioned. The metal barrel is then crimped around the wire, making both an electrical connection and a mechanical connection therebetween. Serrations are sometime provided on the barrel, and generally extend circumferentially around the barrel, although other configurations are possible. The serrations are provided to enhance the mechanical and electrical characteristics of the connection.
The crimp type barrel terminals are acceptable in many applications, however when large gauge wires are to be crimped, problems arise. In order to accommodate the large gauge wires, a large mass of material is required for the barrels. Consequently, the crimping operation becomes difficult and unreliable. Also, heavy gauge metal is generally not required for the other portions of the terminals. Accordingly, considerably more material is utilized in the manufacturing of such heavy gauge terminals than is needed. In the alternative, if the thickness of the barrel portions are reduced to the thickness required for the other portions of the terminals, then the heavy gauge wire will not be properly retained within the crimped barrels.
Another common problem with barrel terminals, is the range of wire sizes with which any given barrel size can be used. In most barrel terminals, only a range of two or three gauges of wire can be crimped effectively. If the barrel is too small, the wire is not properly retained, and if the barrel is too large, the wire does not fill up a sufficient amount of the barrel cavity to provide the required electrical contact and mechanical tensile strength. More specifically, in the case where the wire is too large for the barrel, the barrel tends to relax excessively, thereby reducing the effectiveness of the electrical contact as well as reducing the tensile strength. Consequently, any given barrel terminal is generally limited to a small range of wire sizes.
Also, in the case of barrel terminals, air and other corrosive elements can react with the barrel and the exposed wire to cause corrosion and the like. This corrosion decreases the effectiveness of the electrical connection between the barrel and the wire, as well as reducing the tensile strength therebetween.
Still another problem encountered with conventional barrel terminals is directly attributable to the relatively large crimping force required in order to extrude large gauge wires and stranded wires so that a good electrical and mechanical connection is made therein. In many case this relatively large crimping force precludes the crimping of the barrel which have had plastic sleeves placed thereover. In such cases, crimping must be done before the plastic sleeve is placed over the terminal, which requires an extra manufacturing step.
As was stated, the second group of connectors relates to fiber optic connectors. There are many fiber optic connectors available in the market place. Since the development of the art of transmitting light through fine fibers of glass and plastic material there has been a constant search for satisfactory methods and devices for splicing and coupling the fibers. Such methods and devices have encountered many substantial problems including both the light loss at the connection points as well as the difficulty in working with the extremely fine fibers.
Because of the extremely small dimensions of the light transmitting fibers, it has been more common to connect bundles of cable made up of a plurality of individual fibers. In such cases it is not necessary to have a one-to-one alignment of the individual fibers. However, the bundle must be placed in such position that there will be a substantial amount of light transmitted from cable to cable without an unacceptable loss of light.
Unacceptable light transmission across splices occurs for several reasons. As stated above one reason for light loss is due to the misalignment of the fibers. However, another source of light loss is caused by damage to the fibers. This damage is a result of uneven forces being exerted on the fibers. This causes an uneven deformation of the fibers, which results in light being deflected away from the axis of the fiber. Consequently, inadequate light is transmitted, causing a system failure. This is an unacceptable result.